The most prominent feature of these nuts is their knurled outer surface. The knurling, which can be in the form of straight or diamond - shaped patterns, significantly increases the friction when handling. This design allows for easy manual tightening and loosening without the need for additional tools. In applications where quick adjustments are required, such as in some machinery, equipment, or DIY projects, the knurled surface provides a convenient solution. For example, in the assembly of small - scale furniture or the adjustment of certain components in electrical devices, users can easily manipulate the nuts by hand, saving time and effort.